246 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 9 



ters by which this species was different from species of Caulan- 

 thus. The calyx in Caulanthus was described as urn-shaped and 

 more or less closed, while in Chlorocrambe it is open; the petals 

 of Caulanthus were thought to be of the type seen in C. crassi- 

 caulis, narrow, channeled, crisped and recurved, while in Chloro- 

 crambe they are flat, dentate, and have short claws; the stigma 

 of Caulanthus was described as conspicuous and two-cleft, while 

 in Chlorocrambe it is entire and small These characters do serve 

 to distinguish it from such species of Caulanthus as C. crassicaulis, 

 C. major, C. glaucus, and C. pilosus. These are the species near- 

 est to it geographically. If Caulanthus is accepted in the larger 

 sense, however, these characters alone are not sufficient to war- 

 rant its generic segregation. In Caulanthus anceps, for exam- 

 ple, the sepals are spreading and the calyx not at all urn-shaped; 

 in C. lasiophyllus, C. Cooperi, and C. anceps the petals are 

 flat and the proportions of the claw and the blade not essen- 

 tially different; in C. amplexicaulis the stigma is quite entire. 

 There are two characters at least possessed by C. hastata that are 

 not admitted to Caulanthus — the toothed petals and the definite 



stipe. 



In spite of its several points of agreement with species of 

 Caulanthus and its habital resemblance to certain species, the 

 evidence at hand goes to show that this plant has more probably 

 been derived from Thely podium or some immediate ancestor of 

 that group than from Caulanthus. The evidence for this con- 

 clusion may be summarized as follows: first, the presence of a 

 stipe is unknown in Caulanthus but is of common occurrence in 

 Thelypodium; second, the inflorescence is more suggestive of 

 the primitive species of Thelypodium or even of Stanley a than 

 of any species of Caulanthus ; third, its geographical position 

 argues for its relationship to Thelypodium rather than to Cau- 

 lanthus; finally, the entire stigma is common to all species of 

 Thelypodium but is found only in the primitive species of Cau- 

 lanthus, with which C. hastata does not agree in other respects. 

 Only a few collections of C. hastata are known but it would ap- 

 pear that those individuals from Oregon possess a longer stipe 

 than do those from Utah. If this prove to be true it would indi- 

 cate that the Oregon form is the more primitive. Since it is in 

 this region that the primitive species of Thelypodium occur this 

 would argue for a common origin. 



The question now arises as to the advisability of transferring 

 this species to Thelypodium rather than keeping it up as a mono- 



